list_billing_usage

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries full burden. It discloses default behavior (exclude zero-quantity meters), grouping by datacenter, and filter option. However, it doesn't mention pagination or output format, which is acceptable for a simple list tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise (4 sentences), front-loaded with the main purpose, and efficiently covers key features. No fluff or redundant information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given no output schema, the description provides good context: what is returned (metered quantities grouped by datacenter), default behavior, filter, and a hint for FOCUS output. It lacks explicit output fields but is sufficient for a billing tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the schema already documents all parameters. The description adds minimal value (e.g., mentioning metered quantity types) but mostly restates schema descriptions. Baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool aggregates resource usage for the current billing period, with a specific verb ('Get') and resource ('aggregated resource usage'). It distinguishes from siblings like get_billing_usage_by_datacenter by specifying contract-level aggregation with optional datacenter filter.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides context (current billing period, exclude zero by default) but does not explicitly state when to use this tool versus alternatives like get_billing_usage_by_datacenter or get_billing_invoice. It lacks explicit when-not or alternative guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.